Nuvoton recently released a new motor driver IC that specifically targets applications in 48-V data centers. The KA44370A is a single-phase, full-wave gate driver IC designed for auxiliary fan motors in AI-heavy data centers. In this piece, we’ll examine Nuvoton’s new IC and the shift from 12 V to 48 V in the data center.
The KA44370A is designed for 48-V data centers. Image (modified) used courtesy of Nuvoton
New Gate Driver for 48-V Data Centers
Operating within a supply voltage range of 8 V to 76 V, the KA44370A can directly drive both high- and low-side N-channel MOSFETs to facilitate efficient motor operation. The solution (datasheet linked) integrates several advanced features for optimized motor control, such as speed feedback control with both PWM and DC input methods. It also includes programmable memory for customizing parameters such as speed feedback, advanced phase control, and motor lock protection times.
The IC can drive motors with sinusoidal or trapezoidal current waveforms, which provides engineers with the design freedom to optimize their operation, specifically when balancing low vibration with high-speed performance.
KA44370A block diagram. Image used courtesy of Nuvoton
The IC operates within an ambient temperature range of -40°C to 105°C and a junction temperature range of -40°C to 150°C. The output voltage for the high-side MOSFET gate drive is between 7 V and 11 V at a 0-mA load, with an output current capability of ±100 mA for both high- and low-side gate drive outputs. The KA44370A is also notable for its extensive protection mechanisms, including under-voltage lockout (UVLO), thermal protection, and motor lock detection, along with a current limiter to safeguard against overcurrent conditions.
Supporting the Leap From 12 V to 48 V
At the highest level, the 48-V architecture enables more efficient power delivery at higher loads due to dramatically reduced power distribution losses. Since power loss is proportional to the square of the current (P = I2*R), using a higher voltage allows the same power to be delivered with a lower current, significantly reducing energy waste in power distribution.
Consider the example of a 12-V distribution network delivering 12 kW of power (1,000 A at 12 V). With a cable impedance of 0.1 mΩ, this 1,000 A of current translates into roughly 100 W of power lost (converted into heat) just in distribution. At 48-V distribution, however, this 12 kW only necessitates 250 A, resulting in 6.25 W of power loss and heat generation. A 48-V distribution bus significantly improves overall energy efficiency and less heat generation.
48-V power systems minimize distribution losses. Image used courtesy of Panasonic
48-V systems enable better power density in many ways. First, less current means thinner cables can be used, saving space and improving airflow within server racks. Minimized thermal generation means a reduced need for exotic cooling systems, which are notorious consumers of space and power in the data center. Finally, power supply units (PSUs), which claim ample space in a server rack, are now expected to handle lower currents, meaning they can also be more efficient and compact.
An Industry-Wide Transition to 48 V
The modern data center is transforming to support the exponential growth of AI computation. While conventional data centers have traditionally relied on 12-V busses for power delivery, modern data centers are now shifting toward a higher-voltage, 48-V bus.
Typical application of the KA44370A. Image used courtesy of Nuvoton
The data center’s shift from 12 V to 48 V is not an isolated event. Other high-power applications, namely electric vehicles, are undergoing a similar transition, where legacy 12-V auxiliary electronics are being replaced with 48-V solutions. In this context, Nuvoton’s new motor drives address a true multi-industry challenge. As more applications transition to higher-voltage power distribution, new solutions like the KA44370A may soon replace legacy ICs and components.
